The prior art discloses rotary slide valves which, using a plurality of cross section adjustment members, set different flow cross sections for different flow rates, the cross section adjustment members either being connected tightly to one another so that they each execute the same rotary motion and thereby set one or more flow cross sections, or are driven and controlled by one actuator at a time. Rotary slide valves for setting a liquid or gaseous volumetric flow, in particular in the jacket surface of each cross section adjustment member have at least one flow opening which, depending on the angular position of rotation of the cross section adjustment member, can interact with a feed and/or discharge for the medium which is formed on the housing of the rotary slide valve. Depending on the angular position of rotation a flow cross section is set by intersection of the respective flow openings with the feed or discharge. Due to the rotationally fixed connection of the cross section adjustment members, the different flow cross sections cannot be set independently of one another. The use of several actuators is indeed simple, but this solution requires a larger installation space and is more costly.
In order to prevent unintentional outflow of the flow medium, interposing a seal between the cross section adjustment member and the base member is known. Conventionally, it is an elastically deformable sealing element. The sealing element always fits tightly against the cross section adjustment member and the base member when the cross section adjustment member moves rotationally. Uniform contact forces of the seal against the cross section adjustment member, however, can only be set with difficulty based on the shape of the rotary slide valve. Moreover, problems arise in crossing of the cross section adjustment member flow cross section by the sealing member since it can be damaged when crossing by sticking and eversion.
Furthermore, rotary slide valves are known in which at least one cross section adjustment member is pivoted in a base member. Generally, a slide bearing is formed by the jacket surface of the cross section adjustment member and the inner surface of the base member. In this way the cross section adjustment member is guided or supported at least radially in the base member. Due to the slide bearing arrangement, local friction occurs, but this can be kept low by a correspondingly favorable material pairing. In this case, however, there is the disadvantage that a solid or a particle of dirt which is present in the coolant circuit can stick between the cross section adjustment member and the base member. The result would be failure of the rotary slide valve. Conventionally, this is prevented by the gap of the slide bearing arrangement being chosen to be sufficiently small such that as much as possible no solids end up between the cross section adjustment member and the base member. But this leads to increased fabrication expenses and higher production costs. Alternatively, it is known that the gap can be chosen to be sufficiently large such that the solid/solids is/are conveyed through the rotary slide valve between the cross section adjustment member and the base member. But here the cross section adjustment member may become tilted and thus jammed in the base member.
Therefore, the object of the invention is to devise a rotary slide valve with a plurality of cross section adjustment members which allows clearance of an individual flow cross section and circumvents the aforementioned disadvantages.
Another object of the invention is to devise a rotary slide valve with at least one cross section adjustment member and one base member which easily circumvents the aforementioned disadvantages and ensures permanent and reliable sealing.
Another object of the invention is to devise a rotary slide valve with at least one cross section adjustment member which is pivoted in the base member and which easily and inexpensively prevents sticking of the cross section adjustment member in the base member.